Transactions of Nonferrous Metals Society of China
JOURNAL OF RAILWAY SCIENCE AND ENGINEERING
|Vol. 12 No. 6 December 2002|
（1. State Key Laboratory for Mechanical Behavior of Materials, Xi′an Jiaotong University,Xi′an 710049, China;
2. Department of Materials Science and Engineering,
Shaanxi University of Technology,Hanzhong 723003, China）
Abstract:The differences of transformation behavior between Ni-rich TiNi shape memory film (SMF) and shape memory alloy (SMA) age-treated at 773K after solutiontreatment at 973K have been investigated, using Ti51.5Ni thin film and Ti-51.5Ni bulk alloy as examples, by differential scanning calorimetry (DSC), SEM and EDX. It is found that the age-treated Ni-rich TiNi SMF and SMA are of the same types of transformation, i.e., A→R→M(during cooling), and M→A (during heating) (A: parent phase; R: R-phase; M: martensite); the transformation temperature of the TiNi SMF is lower than that of the SMA, but the SMFs hysteresis is larger. The transformation heat of the TiNi SMF and SMA is nearly the same. The reason that TiNi SMFs strain is sensitive to temperature is not hysteresis, but its thickness is thinner, and the temperature is easy to distribute homogeneously.
Key words: TiNi thin film; TiNi alloy; shape memory film; shape memory alloy; transformation temperature; transformation heat; temperature hysteresis